Well mould is a bit of a misnomer and several things seem to be called this, even when they are not. However things like age marks normally show as bruises under the plastic or dark brown/black dots on the plastic with faded out edges; pin dot which is actually ingrained dirt shows as lots of tiny little black dots [like the pony has black heads...yuck!]. Where as regrind is typically a bright pink or yellow and it almost looks as though the plastic has bleached out.